A former U.S. national security advisor during the former Donald Trump administration claimed in his latest memoir that Trump's key aides had disagreed on several points with South Korea's then-Moon Jae-in administration regarding engagement with North Korea.

In the book titled, "At War with Ourselves: My Tour of Duty in the Trump White House," H.R. McMaster, who served as national security advisor from 2017 to 2018, recalled differences of opinion during Moon's visit to Washington in June 2017 for a bilateral summit.

While Seoul insisted on adding the prospect of negotiation with Pyongyang in a joint summit statement, and an acknowledgement that it would lead any related effort, Washington insisted on emphasizing sanctions enforcement to persuade the regime that denuclearization was in its best interest.

There was disagreement on the North's motive behind nuclear armament during Moon and then-U.S. Vice President Mike Pence's post-summit talks, where Moon believed that Kim Jong-un needed nuclear weapons for defense. Pence, for his part, stressed the need to consider that Kim wants the weapons for offensive purposes.

McMaster also mentioned an incident in July 2017, when his then-South Korean counterpart Chung Eui-yong said the Moon government was not ready to call the North's recently fired Hwasong-14 liquid-fuel intercontinental ballistic missile(ICBM) an ICBM.

McMaster, in response, said just because Chung did not call it an ICBM, it did not mean that it was not an ICBM.